1. Field of the Invention
The invention relates to level sensing assemblies for measuring the level of a fluid in a vessel. More particularly, the invention relates to modifying a float level sensing assembly to a non-float level sensing assembly to measure the level of water in a vessel.
2. Description of the Related Art
There are many situations that require an accurate reading of a fluid in a tank or vessel. While many of these tanks are pressurized, fluid level measurements are also important in non-pressurized tanks. Accurate fluid level measurements are important in order to maintain a system operating as it is designed. Fluid level measurements are important because they can be used to warn an operator of a system that the fluid in a particular tank is about to empty. In many situations, the system that requires the fluid in the tank may be damaged if the level of the fluid in the tank drops below a certain level.
One example of a system that requires a monitoring of a fluid level within a tank is a boiler system. Steam boilers have feed water controls that are responsible for the level of fluid, e.g., water, in the boiler. As the boiler boils the water to create steam, a source of water must supply water to the boiler. If the boiler runs out of water, the boiler will be damaged or destroyed because the steel that creates the boiler cannot transfer the thermal energy it receives away from itself at a rate sufficient to avoid damage thereto. In other words, the boiler requires a sufficient supply of water therewithin.
Referring to FIG. 1, an embodiment of a prior art fluid level sensor is generally indicated at 10. The fluid level sensor 10 is in fluid communication with a tank 12 that has a fluid 14 therein. The fluid 14 defines a fluid level 16.
The fluid level sensor 10 includes a measuring vessel 18 with a water port 20 and a steam port 22 disposed on either end thereof. A fluid level 24, shown in phantom, represents the fluid level 16 in the tank 12.
The fluid level sensor 10 includes three separate and independent systems for measuring the fluid level 24 in the measuring vessel 18. The fluid level sensor 10 has a mechanical float mechanism, generally shown at 26 that includes a float (not shown) which extends into the measuring vessel 18 to float on the fluid level 24. The fluid level sensor 10 also includes a glass gauge 28 that allows an operator the ability to visually identify the location of the fluid level 24 within the measuring vessel 18 without having to open the measuring vessel 18. The third mechanism for identifying the fluid level 24 in the measuring vessel 18 includes a set of tricocks 30 that may be opened to identify what flows out of each of the set of tricocks 30. The measuring vessel 18 includes an auxiliary port 32, which receives a plug 34 therein.
Referring to FIG. 2, the measuring vessel 18 of the prior art is shown prior to installation. The measuring vessel 18 is shipped to a site for installation with the mechanical float mechanism 26 secured thereto (although not shown in FIG. 2 for simplicity). Inserted into the auxiliary port 32 is a temporary plug 36 and a positioning cylinder 38 disposed therewithin. The positioning cylinder 38 is coaxial with the temporary plug 36 and extends down into the interior 40 of the measuring vessel 18. The positioning cylinder 18 is typically fabricated of cardboard. The positioning cylinder 38 is used exclusively for maintaining the mechanical float in a particular position during shipment of the measuring vessel 18 to the site of installation. The positioning cylinder 38 and temporary plug 36 are removed upon reaching the site of installation and the auxiliary port 32 is immediately plugged with the plug 34 for continued operation of the measuring vessel 18 through its life.
The problem with the three mechanisms for identifying the fluid level 24 within the measuring vessel 18 is that they are very insensitive and, when translating the mechanical measurement to an electrical signal, inaccurate methods for measuring a fluid level such as the fluid level 24. If an operator is not present to view the glass gauge 28, or the glass gauge 28 is dirty or corroded such that the fluid level is not visible therein, the method of using the set of tricocks 30 or the mechanical float mechanism 26 reduces the fluid level sensing assembly 10 to one that is very cyclical with the fluid level either being too high or too low and rarely being at an optimal level for operation. This increases the costs of energy as more energy is consumed when the level of fluid in the vessel 12 cycles through such a large range of fluid levels.